In recent years, as development of a high-speed information processing apparatus has progressed, power consumption of the information processing apparatus tends to increase. In particular, this trend is remarkable in an information processing apparatus provided with a large number of high speed interfaces. In view of the above, it has been an important issue to reduce power consumption required for signal transmission.
Japanese Laid-open Patent Publication No. 2006-148389 (hereinafter, called as “Patent Literature 1”) discloses a technique of optimizing transmission power in an interface configured to perform data transmission between semiconductor devices. Specifically, in the technique disclosed in Patent Literature 1, a determination result of reception quality upon receiving test data is transmitted from a receiver side to a transmission side. The transmission side adjusts an output level of test data based on the determination result from the receiver side. In the technique disclosed in Patent Literature 1, the output level for securing reception quality is optimized by adjusting the output level of test data. In the technique disclosed in Patent Literature 1, when the optimized output level is obtained, the transmission side replaces the test data with ordinary transmission data, and starts transmitting.
International Patent Publication No. WO2003/090374 (hereinafter, called as “Patent Literature 2”) discloses a technique that a receiver side transmits an evaluation result of a received waveform to a transmission side, and the transmission side adjusts an output parameter based on the evaluation result for waveform shaping. Specifically, a transmitted waveform in an output driver in Patent Literature 2 is shaped by allowing the transmission side to adjust an output parameter of the output driver so as to minimize distortion of a receiverd waveform, based on an evaluation result of the distortion of the received waveform transmitted to the transmission side.